Among the radio resource management algorithms in a radio communications system, an admission algorithm is a basic radio resource management algorithm. An admission algorithm determines whether to allow a new service call request for establishing a connection according to the cell load condition. The cell load is a relatively abstract concept and has different meanings in radio communications system using different technologies.
In a traditional radio communications system such as the global system for mobile communications (GSM) and R99 of the wideband code division multiple access (WCDMA), “dedication” is the main idea of resource allocation. When a user accesses a system and resources are allocated to the user, the resources are occupied by the user so long as the user does not disconnect the connection. Therefore, resource utilization can be used to represent the cell load. Taking the power resource as an example, if the actual output power of a base station is more than 90% of the maximum output power, the cell load is considered high. If the actual output power of a base station is less than 90% of the maximum output power, the cell load is considered low. In addition, because the resources are dedicated, the resources may be predicted. That is, the quantity of resources occupied by a new user accessing the system may be predicted according to the current system load condition.
With the evolution of technologies, “sharing” replaces “dedication” and becomes the main trend of resource allocation. After a user accesses the system, the quantity of resources occupied by the user may be determined by a scheduling algorithm, allocated according to the actual need, and balanced according to the priority. In this case, it is improper to use the resource utilization to represent the cell load condition.
Some examples are described herein. Numerous single link enhanced technologies have been introduced in the long term evolution (LTE). For example, the adaptive code modulation algorithm may adjust the code modulation scheme on a real-time basis according to the channel quality and power requirements, multiple input multiple output (MIMO) may implement space multiplexing by using multiple antennas, and the automatic repeat request (arq) and hybrid automatic repeat request (HARQ) form a hierarchical retransmission. Under the influences of these algorithms, “sharing” becomes more and more powerful and flexible. However, the amount of resources used by the same service and even the total amount of available resources may vary to a large degree. Due to the influences of several factors, the calculation of resource utilization becomes complex and inaccurate. Thus, it is no longer proper to perform admission control on services based on the resource utilization.